Curable compositions comprising an epoxy resin and a curing agent are well known in the art. One common application for curable compositions is in the process of repairing existing pipelines (e.g., sewer or chemical pipelines). During this process, a curable composition filled liner is inserted or pulled into a damaged pipe. Once in place, the curable composition is cured with a hot water bladder or steam to form a tight-fitting replacement pipe. The resulting product, deemed a cured-in-place pipe, allows for seamless repair of a pipe with little to no excavation necessary, thereby making the process more cost effective than the alternative methods.
For a curable composition to be adequately applied to cured-in-place applications, the curable composition must (i) have a sufficient latency period (i.e., time to form a gel) to be manageable while inserting into a damaged pipe, (ii) have enough structural integrity to fill the pipe and maintain conformity, and (iii) efficiently cure at temperatures compatible with a hot water bladder or steam. Conventional methods for providing a curable composition with desirable qualities (i), (ii), and (iii), include changing the structure of the epoxy resin or the curing agent, adding a diluent to reduce viscosity and increase latency periods, and adding an accelerator to reduce curing times.
Existing curable compositions provide inadequate results for one or more of the desirable qualities (i), (ii), and (iii). In addition, economic production is also needed. For example, conventional curable compositions typically require high levels of curing agent or accelerator to efficiently cure at temperatures compatible with a hot water bladder or steam, or require a diluent to reduce viscosity and have a sufficient latency period (i.e., time to form a gel) to be manageable while inserting into a damaged pipe. Such additional components increase costs associated with materials and equipment necessary for production of the curable composition.
Thus, there remains an unmet need in the art for improved curable compositions that (i) have a sufficient latency period (i.e., time to form a gel) to permit inserting into a damaged pipe, (ii) have sufficient structural integrity to fill the pipe and maintain conformity, and/or (iii) efficiently cure at temperatures compatible with a hot water bladder or steam.